Automatic switch for telephone systems.



(I. H. NORTH.

AUTOMATIC SWITCH FOR TELEPHONE SYSTEMS.

APPLICATION FILED DBO. 8, 1908.

977,536. Patented Dec. 6; 1910.

4 BHEETSBHEET 1.

. C. H. NORTH. AUTOMATIC SWITCH FOR TELEPHONE SYSTEMS;

Patented Dec. 6, 1910.

APPLICATION FILEHDEO. 8, 1908.

O. H. NORTH.

AUTOMATIC SWITCH FOR TELEPHONE SYSTEMS.

APPLIOLTION FILED DEC. 8, 1908.

- Patented Dec. 6, 1910.

4 SHEETS-SHEET 3.

Enoentoz Mwwzm.

4 G. H. NORTH.

AUTOMATIC SWITCH FOR TELEPHONE SYSTEMS.

APPLIOATIQN FILED no. 8. 190a. E

. I Patented Dec. 6, 191 0.

4 SHEETS-SHEET 4.

Bl IHII To all whom 'it may concern:

UNITED STATES PATENT or-"FIoE.

CHARLES HOWARD nonrn, or CLEVELAND, onro, ASSIGNOB 'ro THE-NORTHELECTBIG I COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

AUTOMATIC SWITCH FOR TELEPHQNE SYSTEMS.

Specification of Letters Patent.

Patented Dec. 6, 1910;

Be it known that I, CHARLES NORTH, a

citizen of the United States, residing. at

Cleveland, in thecounty of Guyahoga and State of Ohio, have inventedcertain new and useful Im rovements in Automatic Switches for TelephoneSystems, of whlch the following is a, specification, reference being hadtherein to the accompanying drawfi ly invention relates to so-calledautomatic switches for telephone systems, that is to say'switchesemployed to effect connection between different lines or circuits, bymechanical means electrically controlled.

It has particularreference to such switches as are used in telephonesystems for selectively connecting a given circuit with any one of anumber of other circuits. The switches heretofore emloyed for thispurpose are well exem 1i ed in Patents Nos.

815,176 and 815,321, granted to Keith-and- Erickson March 13, 1906.

The object of my invention is to produce air, as well as decrease thecostof-"manuac'ture, I make 'these magnet structures interchangeableunits,

Various other points of improvement will sufiiciently a pear from thedetailed descrip'- tion hereina ter and the appended claims.

My invention is illustrated in the accompaiii ying drawings wherein;igure 1 is a side View of a switch embodymfg rpy invention; Fig. 2 is arear view thereo 3 is a plan view of the'same;

Fig. 4 1s a plan view of one electromagnet u mt removed from the frame;Fig. 5 is an end view thereof looking in the direction of the arrow inFig. 4, and showing a-latch unit being the rotary magnet; Figs. 6 and 7v for t e release movement, this particular method of -inserting andsecuring the springs therein. Fig. 10 is a detail view of amodification-for the adjustable pawl stop.

Referring to the drawings, 1 represents a plate upon which the differentparts of the switch are mounted. Upon the back of this plate are-securedthe banks 3 and 4, and upon the front of it a frame 2 carrying thespindle 5 with its wipers, the'operating magnets 6 and 7, and therelease magnet 8. The banks '3 and 4 are alike in their construction anda brief description of one will sufiice for both. The bank 3, therefore,consists of ten straightvertical rows of'ten pairs of contacts each,heldin a body of insulating material, and clamped between side plates 3and 3', each of which is provided with ears 3, through which serews3 areinserted to secure itupon the plate 1. The body of insulation 3, ispreferably built up of layers or curved strips of a'suitable insulatingcomposition, but it may be molded solid, the

contacts in that case being set in the die and the composition moldedaround them. Where the strips are employed, they are slotted or groovedto receive the contacts, which are placed ,therein as indicated in Figs.8 and 9, and then the successive strips piled u from the bank. Vhere theslots are ma e exactly the same width as the contacts, however, there isa tendency for the latter to work loose, and I remedy this by having thestrips molded with the slots from .003 to .008 of an inch shallower thanthe width of the springs. The contacts'being insulated and the stripspiled up", the top and bottom 'plates 39 and 3 are put in position thescrews 3 are inserted assin 7 1 from the top to the bottom plate andtappe i into the latter, the bank is placedin an oven and'heatedsufliciently to soften the compo= sition'a little,'-and then by tiscrews or otherwise forcing the plates 3*" and 3? together, the contactswill be forced into the substance of each strip, both above and below,until the surfaces of the strips meet, thus insuring an absolutely tightgri In Fig. 8 I have shown each contact 3'? wit a small return bend init at 3*, but'with a straight tail on the outside of the bank. The bend3 is for the purpose of. preventing hteni'ng the longitudinaldisplacement outwardly and to I coiled spring is secured at. its innerend upon prevent the same inwardly. I may adopt either ofthe twoexpedients shown in Fig. 8, one on the left hand side, where the contactis giyen aquarter turn outside the bank, the other on the right. hand,where it is given a straight otlset or bend. on the outside. These twomethods may be combined if desired, and it will be observed Fig. .l thatthe offset at 3". ailords an op 'iortunity to increase the insulationbetween the respectivecontacts by setting the offset in oppositedirections in alternate rows and by setting it oppositely for each pairif desired. The contacts are all placed with their surfacc'svertical andthe wipers are slipped around beneath the. rows of contacts until thedesired row is reached, and then pass up that row. This it will beobserved is a reversal of the method employed in the Keith and Ericksonswitches hereinbefore referred to. In those and in all of the Shrewgerswitches the movement is up to the row and then around the row, thecontacts being arranged with theirtiat surfaces horizontal. The verticalarrangement, however, I consider to be better, because it makes thecontacts self-cleaning, which is an important point' in apparatus ofthis character.

The frame 2 consists of a finislied white metal'or similar castinghaving a vertical straight-faced member or body 2, with upper and lowerattaching arms 2 and 2 respectively. Carried upon suit-able forwardextensions 2 2 and 2*, are frontmounting plates 2, 2 and 2". These areof course connected by suitable webs or flanges in casting so that thewhole frame is )roperly braced without superfiuous metal. The arms 2have an intermediate horizontal web..2 carrying the upper bearing forthe spindle 5, and an extension 2 of this web carries the'vertical androtary cutofi' contact springs 9 and 10 which are actuated bythespindle' as it returns to its zero or. normal position A similar webat the bot-tom f the frame carriesthe lower bearing for thespindle,-these .bearings belng formed in i separate collars or bushingsinserted through op'enings'molded in the webs ofthe frame.

The spindle 5 slides vertically and also rotates 1n the bearings 5 and 5This vertical or sliding movement is produced by means of a rack 5",best-shown in Fi s. 1, 6 and 7. This rack does not turn with thespindle, but has upper and lower collars 5 and 5 through which thespindle passes and through which it turns, these collars lying betweenfixed collars. or sleeves 5 and 5 secured 'upon the s indle in anysuitable we as by means of t epins 6. The upper col ar 5 carries therota-r ratchet 5, and the lower collar 5' carries t e casing 5" with-.in which the coiled spring is carried for re-,,

storing the switch to its zero position. This the spindle and its outerend to the casing 5" as indicated at 5 in Fig. 1. The casing carries thepin 5 which slides along the edge of the frame 2 and thereby keeps thetension of the spring constant for all vertical positions. The rack 5has its teeth formed in a peculiar way. Instead of each having one longinclined face and one short face, as usual with ratchet teeth, they areformed by merely milling out or casting in the rack a succession ofapproximately semicircular openings. The pawl 7 cooperating with theseteeth, and which ,is' shown in e'n-- gagement therewith in Fig; 6, hasnot the usual sharp nose, but instead has a squared end, with a slightprojection/7 adapted to fit into the curved indentations in the ratchet.the wear on the parts, and secure it strong grip or engagement betweenthem. The retaining pawl for the vertical ratchet, and the teeth whichcooperate with it are on the side thereof as shown at 5 in Figs. 6 and7, and are of the ordinary conformation.

Cooperating with both the rotary and vertical ratchets is a. doubledetent dog' '11,

pivoted at 12 and having an upper straight member 11 engaging the rotaryratchet,-a lower hooked pawl 11 engaging the side ratchet 5 on thevertical rack, and two tails 11 and 11 the former engaged by theend ofthe armature lever 8" of the release madgnet 8, and the latter'adaptedto engage an to beheld by'alatch. 6 pivoted on the frame G of therotary. magnet (see Fig. 5).

In operation, whe nthe releasemagnet is energized, the lever 8 is thrownover (to the right in ig. 2), the tail 11 of the dog 1.1 is thrown withit and engages the latch 6, being held thereby so that in case therelease magnet is denergized before the By this construction I minimizerelease switch is fully restored, the dog will not be released, and thecomple'te r'estoration of the switch will notbe interfered with. Thelatch 6" is a bell crank pivoted at its'angle and normally heldinlatching position by ajspring 6 bearing upon-its I tail 6. The armaturelever 6 of the; rotary magnet is the first to-move when the switch isactuated, and its first movement, lifting the tail of the latch,releases the dog Il, and permits the pawls 11 and 11*.to engage theirrespective ratchets and thereby properly.

perform every function of holding thespin dle in a position to whichitniay he stopped and until it is again released.

The three magnets 6', 7 and 8 are made-as identical and interchangeableunits.

the several magnets, as well asease-and efli- I be lieve that I am thefirst to succeed man-.-

port for the armature.

ciency in maintenance, since the removal of a magnet and thesubstitution of a new one therefor is but the affair of a. moment. Theonly difference then between the rotary and vertical units, and therelease unit, hes in the provision of a differently shaped pawl, and inthe case of the release unit of no pawl at all.

It will be observed in Fig. 1 that the bifurcated end of the lever 8 isopen, serving to strike, against the inclined tail 11 of the 'detent doIn Fig. 4 I have shown one unit detacl ed, its armature lever beingfitted with a pawl. A description of this unit will suffice for all theunits, and as Fig. 4 is a plan view only, reference may be had.to any ofthe units in the other figures to supplement this illustration. For thepurposes of this description we will assume that Fig. 4 represents therotary unit 6. This mounted on a. frame plate 6", which may be of ironor other suitable metal.

The two magnet cores 6' are secured to the plate by screws 6 (see Fig.5), and are provided with an iron yoke 6, if the frame plate is ofnon-magnet c metal. Along one side of the electromagnets lies anextension member of the frame, 6*, constituting a sup- This armature isformed of a plate of soft iron 6 with an aluminum bell-crank lever 6riveted to it. A long arm 6 of this lever constitutes the continuationof a rib formed up in the aluminum body, and as the lever is beveled offat its end, a bifurcation results, as indi cated at 6, the twosides'ofthe. lever forming cheek pieces for the reception of the awl 6normally held with its oint outy the s ring 6", extending from he tailof the paw at 6 to a. fixed stud 6 Where the unit is to be used forrelease, as indicated at 8 in Fig. 1, the pawl, spring, and stud areomitted. p

The armature plate 6 is scored across.

near the top, so as to'take over the knifeedge 6, formed on a taperedplate 6?, secured upon the top of the frame barb by screws extendingthrough washers and slots in the taper plate. The inclined edge ofthis.v

plate rests against a shoulder 6 formed on the frame plate, andadjustment of'the armature to and from the cores is readily accomplishedby loosening the screws and slid ing theplate laterally, this motionbeing permitt by the slots, and the plate 6 restmg against the shoulder6 in all positions,

so that all strain and wear is taken up by the frame plate. Thearrangement of this shoulder andthe strip are well shown in Fi 1, wherethe ma site at 7 is presentedfin elevation. It should be noted that Fig.

5 shows the unit turned upon its side, with the top tothe left, asindicated by the arrow in that figure;

The armature, and thebell cra'nk lever 6? ceeding tooth. Fig. 2 showsthe adjustable maybe raised or lower'e throw of the pawls 6 and 7 of therotary' and ,vertical magnets res ectively, by fitting slides to theframe mem er 2, as indicated in Figs. 1 and 2. It is particularlyimportant ,that the motion of the actuatingpawls be positively limited,in order to avoid any over throw, and to positively with-draw each pawlfrom its ratchet when its armature retracts, so that it may fall intothe suclimiting plate or slide for the vertical pawl. which is marked 6-in that figure and 7* in Fig. 1. By loosening the holding screws, andslidin theplate slightly from side to side, the edges of the op ning yin the plate d as required.

In operation, when the pawl is thrown up by the action oft-heimagnetitsnose 7 is forced into one of the indentations in the with it. 1 As theupper edge of the pawl comes against the upper end of the openingvertical ratchet, so that it carries the spindle throwing, or movingmore than the single step intended. As the pawl drops, its lower edgestrikes the lower edge of the opening 3 and it slides out, tensioningits spring 6, ready to engage the next tooth if the magnet is againenergized. This transverse plate may be made in two parts, or ratheutwoseparate plates for upper and lower stops of the pawl 7 may be provided,the upper one presenting its lower edge to the pawl, and the lower oneits upper edge, assho'wn in Fig. 10. These adjusting plates are all ofsteel, may be case-hardened, and afford a means for very accurate.adjustment of the parts and of their movements. I consider that thebroad rinciple involv'ed in the use of these plates 1s original with me,and that they formimportant elements of't-he switch structure, hence Ishall claim. the samelaccordingly. In assembling this switchytheframe 2secured to the plate 1 through the medium of short posts 12, by.screwspassin through the ends of the arms 2 and 2 T e length of these, postsis, sucli that when the screws areset up, the spindle 5 is centered withregard to the ourvlitur'ejof the 'Ibanks, so

that its wipers 5 and 5 (see Fi s. l and 3) i as identical andinterchangeable self-con will cnga e il'h, contacts 1n the anks when thespind e is ro ated by the magnet 6 and raised by the magnet 7 Inoperation the magnet 6 works first, turning the spindle until the wipersw and :13 come under the desi d row of contacts, the spindle being heldin position by the nose 11 on the dog 11, engaging the rotary ratchet 5The spindle and its wipers are then raised step by step through theagency of the magnet 7, until the wipers rest upon the desired contactsin'the row selected. The switch is adapted to be used for any purpose,and in any circuit, eitheras a selector or connector. To restore it tozero, the magnet 8 is energized, attracting 'its armature and causingthe end of its lever 8 to force over the tail 11 of the dog 11 until thetail 11 engages and is held by the latch 6* on the rotary mountingplate. The detents 11 and 11 are then disengaged from the respectiveratchets 5 and 5, and the spindle drops of its own weight until thewipers have cleared tlie j- -if'ou with which they were engaget l, afterwhich the spring in casing 5" turns the spindle back to the zeroposition in the drawings.

For convenience in making connections, I provide aset of jacks on thelower portion of the plate 1, as indicated at 15, cooperating blades 16being carried on the lower part of the frame '2. The jack springs 15 aremounted in an" insulating strip and extend through to the back oftheplate for ready access in wiring, and'the upper ends of the blades 16are notched for connection to the terminal wires of the magnets and thewipers. I

I am aware that some changes may be made in matters of detail in thisstructure,

without affecting the design or the essential, features of my invention.I wish it thoroughly understood'that all such non-essential changesormodifications are contemplated by me, if Within the scope of theappended claims. Having thus described my invention, what I claim andilesire to ---ecure by Letters Patent of. :the State), is: p

1. An automatic switch comprising'rela- 'tively fixe'd "contacts, arelatively movable selective eontact, and a plurality of electroma netshavingm'echa-nieal connection with am control: of said movable contact,all of;

said electroma net structures being identical and micro angeablej units.

.2. In an electrlcal swltch, a contact bank,

. a cooperating wiper, and a plurality'of e'lec-- 'tr'omagnetscontrolling the l wiper, each of said magnets.comprising'- azpain'o'fspools, a

frame, an armatgreand, armaturelever, and

means alto-the 'end'of the lever for attachin" lel-pawl,- and "all ofsaid-magnets being mad:

ofmagnet cores and spools wit tained units. I

3. In an electrical switch, relatively fixed contacts, a relativelymovable cooperating contact, and a plurality of e'lectromagnets tocontrol said movable contact, all of said ma nets bein identical andinterchangeable sel -containe units, and each comprising, a frame, apair of cores carrying spools there on, a knife-edge on the frameadjacent to the ends of the cores, an armature fulcrumed on theknife-edge and extending across and in juxtaposition to the cores, andan armature lever extending forwardly parallel to the cores and beyondthe frame with retracting. springs secured to the frame.

4.111 an electrical switch bank contacts and a coiiperatin-g movablewiper contact, with a plurality of controlling magnets therefor allformed as self-contained identical and interchangeable units, and eachcomprising a frame or return bar with an end plate for attachment to theswitch frame, a pair of cores and magnet spools mounted on theend platewith a suitable connecting yoke, the cores extending parallel to .tlreframe a knife-edge on the frame adjacent to the free ends of the cores,an armature fulcrumed upon said knife-edge, a

rality of identical and interchangeableselfcontained actuating andcontrolling elements for said ratchets, each comprising the followinginstrumentalities: a separate frame, a pair of magnet cores and spoolsthereon, an adjustable knife-edge, an armature fulcruined on'theknife-edge, an armature lever extending from above the knife-edge tobeyond the end of the frame, means for attach ing an actuating pawl tosaid lever and re" traeting s rings for the armature serving alsoto hol'crum.

(5. In an electrical switcln' relatively fixed the same in positionu'ponits fuland relatively movable contacts, and a plu' rality ofelectromagnets for producing variable eoiirdination between saldcontacts, said.

electrom'agnets being identical and interchangeable self-containedunits, each com- .prisin the following instrumen alltieszay- 125 asuitable;

frame' having a right angle end iece, a pair ma n'et-ic yoke mounteduponv the end piece ant? extending parallelw'ith the frame, an

an armature lever of greater length than the frame ext-ei'iding over thetop thereof and bifurcated at its end toreceive an actuating pawl, and apair ofhelical springs secured atone end to the frame. and at the otherend to the ari'imtureabove the knife-edge, Whereby the lever is normallymaintained in a depressed position, and the'armature is kept upon itsfulcrum.

7. In an electrical-switch, relatively'fixed and relatively movablecontacts, and, a plurality of actuating electromagnets thereforconstituting identical and interchangeable units, each comprising a coreand spool, a frame, and an armature and retracting springs therefor, anda knife-edge fulcrumed for the armature consisting of a tapered strip ofhardened steel with a straight knifeedge and an inclined back, togetherwith slots extending parallel to the back, and screws in the samesecuring the strip on the frame, with its inclined back resting a ainstacomplementary inclined shoulder or ange formed on the frame, wherebylateral movement of the strip will'result in longitudinal adjustmentof-the armature to and from the magnet cores, and when set the parts maybe locked on the frame, with the back of the strip against a solidabutment to take up all shocks of pounding. H

In testimony whereof I aflix my signature in presence of two Witnesses.-

" CHARLES HOVARD NORTH.

\Vitnesses: 4

GEO. H. FISTER, I

EDWARD E. CLEMENT.

